Building a 300B PSE

[MGCRead]

Hello, I have just joined this forum as I am sure it will prove useful as I am considering building the 300B PSE having bought the transformers about 20 years ago !

I am currently studying the build instructions and circuit diagrams. The earthing puzzles me. I would expect the case to be connected to the mains earth but the parts list states R24 ( 10 ohm, 2W ) connects the mains earth to the earth post. As the earth post is on the case it will be grounded through R24, is this safe? The wiring diagram on page 9 show the mains earth directly connected to the case which is what I would expect. Can anyone clarify this for me please. I don't want to start building until I understand the circuit better.

The transformers are isolated from the case, as are the signal terminals, but the choke is not.

Any help will be much appreciated.

Thank you, Malcolm